The mistaken killing of a missionary and her daughter in Peru underscores the serious peril that many face. Believers say that fearlessness is the essence of their calling.

He's smuggled Bibles into China, Laos and Iran. He's been detained and interrogated by machine gun-toting soldiers of the Palestine Liberation Organization. He's tended to those who have lost limbs, homes and family members to rebel violence in southern Mexico.

Matt Thompson is just 23, and looks every bit the college student he is in flaps and a faded T-shirt. But already he's put in six long years in the riskiest kind of missionary work there is: reaching people in places that are hostile to Christian evangelism.

Recent headlines have underscored the perils and pitfalls that tens of thousands of Christian missionaries willingly face in following the biblical mandate, known as the "great commission," to spread the gospel of Jesus Christ throughout the world. Last month, the Peruvian military mistook an American missionary plane for a drug smuggling flight and shot it down, killing Veronica Bowers and her 7-month-old daughter. A year ago, an Australian missionary was burned alive with his two sons by a Hindu mob. And in Colombia, more than 50 pastors have been killed and 300 rural churches burned in the last few years, according to Terry Madison, president of the Santa Ana-based Open Doors USA, part of an international mission organization that specializes in assisting persecuted Christians.

The Southern Baptist Convention, whose 4,865 missionaries in 153 countries make up the nation's largest evangelical mission force, says it has lost 53 workers to violence since entering the field in 1845. Missionaries daily face the threat of snakebites, drownings or other perils: Last May in the Ivory Coast, carjackers shot at a missionary and drove off with his 2-year-old son in the car. The boy was recovered, according to Mark Kelly, spokesman for the convention's International Mission Board.

Believers like Kelly and Thompson say simply that fearlessness in the face of risks is the essence of faith in God.

"Even in dangerous situations, if you really believe that there is a God who is all-powerful, the safest place to be is in the center of his will," Thompson said. "Why be scared? God will take care of us."

Experts say most missions run smoothly without major incident, and that dangers ebb and flow depending on a particular country's circumstances. Ever since the modern missionary movement began in Europe in the 18th century--and in the United States in 1812--the work has always carried risks.

Madison, who entered the mission field in 1968, recalled that a friend had to run for hours to escape headhunters in what was then known as "Cannibal Valley" in Papua New Guinea. Paul Pierson, dean emeritus of Fuller Theological Seminary's School of World Mission, was placed under house arrest for subversion while serving as a missionary in Brazil in 1964. At the time, he said, Christian missionaries who supported social reform--to reduce, for instance, the enormous gap between rich and poor--were suspected by the military rulers of sympathizing with communism.

During the Cold War, the Soviet Union and its satellite nations severely repressed evangelism outside the traditional churches, Madison said. Today, religion is blossoming in former communist countries. But rising religious fundamentalism and regional strife in many parts of the world present new risks.

His organization, Open Doors, is focusing on the region from West Africa to Asia, where he says 97% of the world's least-evangelized people live. The area is home to 1.6 billion Muslims, Hindus and Buddhists, and is known as the "10-40" window because it extends from the 10th to the 40th parallel north of the equator.

Although Open Doors specializes in hostile countries, other agencies adopt different strategies. The Church of Jesus Christ of Latter-day Saints and the International Church of the Foursquare Gospel, for instance, say they do not enter countries without the express permission of government authorities. Ron Williams of Foursquare explained that the organization's focus on establishing new churches overseas requires government cooperation, and added that the Bible counsels believers to obey the laws of the land.

Others, however, amicably disagree. "In our view, the laws of God supersede the laws of man," said Mike Yoder of Open Doors. "God says to take the Gospel throughout the world, not just where man has legally decided you're allowed to go."

Pierson said Fuller Seminary has taught courses on ministering in hostile nations, and most mission boards say their members are given emergency plans of action. To many missionaries, one of the most important components is the prayer networks activated during times of need.